The present invention relates to an integrated circuit socket, and more particularly, to an integrated circuit socket with a contact pad.
With the rapid development of the semiconductor industry in which the density of integrated circuits (ICs) has gradually become higher, the gate length has been decreased to sub-micron range, even to the deep sub-micron. Nevertheless, the lifetime of products has become much shorter. Since the variable requirement with IC devices also has increased, there are products with different functions, sizes, and pin assignments.
In the processing steps of semiconductor devices, there are many test procedures after IC devices are created to ensure the functionality and quality of the IC devices. For example, these test procedures of an IC chip may include an examination of lead frame, power consumption, the basic logic analysis, the output impedance measurement and the xe2x80x9cBurn-inxe2x80x9d test. The basic hardware configuration of these test procedures is to use a socket or a connector to locate the IC chip.
The conventional connector of the IC chip, such as logic circuits for central processing unit (CPU) or memory unit, is all with specific usage and pin assignment. As the IC chip is in a xe2x80x9cburn-in testxe2x80x9d, conventional sockets are designed for a specific kind of an IC chip. A clamping structure in the socket is used to fix the IC chip and conduct it for testing. Since the conventional clamping structure is designed for pin contact, the way may get the surface of the solder balls pierced, which is harmful to solder balls and results in the damage of the solder balls. Testing current circulating among the contact interface is blocked with ease, causing high contact resistance values so that the whole electrical contact of the IC chip is obviously degraded.
Therefore, the contact interface must be kept in a good electrical contact to form a preferred contact region between solder balls and contact pad, making current circulate easily, that is to say IC chip must to be exactly located in the contact pad. However, the conventional pin contact is apparently disadvantageous to circulation of current since the contact region is too smaller. Further, a none damage zone (NDZ) is defined as an essential contact region where is used to solder IC chip with the printed circuit board (PCB). The good condition of the NDZ, including geometric shape and electrical property, needs to be held all the time during IC testing so as to contribute to exactly solder NDZ with the PCB after the IC chip is completely tested.
In view of the foregoing regarding the conventional integrated circuit (IC) socket, there have been various problems all the time. The primary object of the present invention is to provide an integrated circuit socket with a contact pad.
According to the main object, the present invention offers an integrated circuit socket with a contact pad, wherein the contact pad comprises:
(1) A base unit which further includes a base, a contact pin and an elastomer wherein the elastomer is located at the upper portion of the base and the contact pin is fastened inside a recessed portion of the base.
(2) An interposer which further includes contact pads, conductive wires, pads, a flexible film, a stiffener, a stop layer and positioning holes. These positioning holes are used to match up with the base unit in order to assemble exactly the IC socket by dowel. In operation, the contact pads, located on the center of the interposer, are contact with the solder balls of the IC device. Electrical signals are transmitted from the IC device to the contact pads, and then pass through the coupling conductive wire to the pads, finally come over the contact portion of the contact pin to the circuits of the PCB.
(3) An adapter unit, which includes an adapter and a depressor, is placed on the base unit and the interposer and the adapter unit provides the positioning function of IC device and the depressor can suppress or release the IC device.
(4) A cover unit which is located over the base, the interposer and the adapter unit, and includes a cover and a spring such that the cover is coupled to the depressor of the adapter unit and is capable of vertically moving up and down.
According to the present invention, the contact type between the solder ball and the contact pad provides a preferred protection and also does not tend to contribute to deformation resulting in an ineffective electrical contact. Further, the electrical contact is better since the contact type between the solder ball and the contact pad is line or surface contact in partial region. Furthermore, a NDZ can be readily kept in a good condition so as to form a preferred contact interface and the deformation of the solder ball is smaller than that of the conventional pin contact.